RF Mosfets

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "RIAA/MPAA's Worst Nightmare" <mike.marcum-at-zoomtown-dot-com> 

Some posted earlier in the list of some massive mosfets (1800W Pd, .11 ohm 
Rds-on, 500v, 48A, 30 MHz). Part # DE475-501N44A. These aren't as bad price 
wise as I expected. I got them for $71.05 each plus shipping (100+ gets 
discount). Could these be run past their current rating with slower 
switching (never heard of a 30 MHz tesla coil, 5 MHz rarely) as long as the 
Pd isn't exceeded? Anyone got any links to calculate power dissipation with 
certain voltage ,current, waveform, frequency, and ambient temp? I'm 
waiting on a quote from another company on a slower version of these (high 
power types, 1000W+). Thanks all.